This invention relates to dental prostheses and more particularly to an adjustable support for orienting and holding a prosthetic tooth or appliance at a preselected angle.
The installation of a prosthetic tooth usually requires a foundation implant in the jawbone for receiving a support arrangement for holding the prosthetic tooth. Known support arrangements for prosthetic teeth are usually inserted directly into a foundation implant such as shown in U.S. Pat. No. 4,657,510. The axis of the prosthetic tooth closely aligns with substantially aligned axes of the foundation implant and the tooth support.
Thus the orientation of the prosthetic tooth usually follows the orientation of the foundation implant. If slight changes are needed in the angular position of the prosthetic tooth relative to the foundation implant it is often necessary to machine the tooth or the tooth support to the desired angle, or bend the tooth support to the desired angle. Machining of the tooth support is a costly and time consuming procedure and the bending of a tooth support can cause stress cracking and reduce the strength of such support.
A recent development in response to these problems is a device sold under the trademark Robutment by Ventplant Corporation of Philadelphia, Pa. The Robutment device includes two arms pivoted at a ball joint for adjustment purposes. One arm locks into the jawbone and the other support arm is inserted in a hole in the prosthetic tooth. Since the support arm is generally cylindrical, a drilled hole of precise dimension must be made in the prosthetic tooth to properly accommodate the cylindrical support arm. In order to lock the Robutment device in an adjusted position the exterior surface of an abutment portion must be held rigidly with a holding tool. Tool marks and scratches can thus occur on surfaces that make intimate contact with the mucosa thereby causing irritation. Another disadvantage of the Robutment device is that the prosthetic tooth must be feathered to tapered edge against the surface of the cylindrical support arm, thus requiring precise machining after the tooth is in place.
It is thus desirable to provide an adjustable support for a prosthetic tooth that can be rigidly secured to an implant in a selected position without the need for drilled holes of precise dimension in the prosthetic tooth and without the need for feathering the prosthetic tooth to a tapered edge. It is further desirable to provide an adjustable support for a prosthetic tooth that can be tightened in a desired position without scratching surface portions of the support that contact the mucosa.